Efficient and stable tin perovskite solar cells enabled by amorphous-polycrystalline structure

Abstract

Tin perovskite solar cells (TPSCs) have triggered intensive research as a promising candidate for lead-free perovskite solar cells. However, it is still challenging to obtain efficient and stable TPSCs because of the low defects formation energy and the oxidation of bivalent tin; Here, we report a TPSC with a stable amorphous-polycrystalline structure, which is composed of a tin triple-halide amorphous layer and cesium-formamidinium tin iodide polycrystals. This structure effectively blocks the outside oxygen, moisture and also suppresses the ion diffusion inside the devices. In addition, its energy level benefits the charge extraction and transport in TPSCs. This design enabled us to obtain the certified quasi-steady-state efficiency over 10% for TPSCs from an accredited certification institute. The cell was stable, maintaining 95% of the initial PCE after operation at the maximum power point under AM 1.5 G simulated solar light (100 mWcm −2) for 1000 hours.

Efficient Passivation Strategy on Sn Related Defects for High Performance All‐Inorganic CsSnI3 Perovskite Solar Cells

“…[ 14–16 ] However, compared with hybrid MASnI 3 and FASnI 3 PSCs of a significant leap in PCE over 10%, the potential application of all‐inorganic CsSnI 3 PSCs seriously suffered from the limitation of a low PCE of only around 5%. [ 17–20 ]…”

Solution-processed ITO nanoparticles as hole-selective electrodes for mesoscopic lead-free perovskite solar cells

“…Note that the back-contact electrodes of these regular planar or mesoscopic devices were made by thermal evaporation of silver metal under high vacuum condition that is limited to their future industrial scalability. While the planar devices adopt ~200 nm thickness, closely associated with the effective charge diffusion length, for high-performance tin perovskites in solar cells, 14,15,27,28,[32][33][34]41 the 1 μm thick Al 2 O 3 insulating film in the mesoscopic devices is too harsh in terms of effective charge carrier diffusion for the tin perovskites. The further improvement in PCE is likely made by decreasing the Al 2 O 3 thickness.…”

“…9 Such tin-based perovskites have been extended to other applications such as transistors, 10 photodetectors, 11 light-emitting diodes 12 and lasers. 13 For highperformance PSC, tin perovskites have evolved on suppressing oxidation of tin (from Sn 2+ to Sn 4+ ), pinholes and surface defects while improving crystallinity through an exploration of hybrid cations or anions, [14][15][16][17][18][19][20][21][22][23] additives [24][25][26][27][28][29][30][31][32][33] and interfacial engineering. [34][35][36][37] The additive approach is effective regardless of the type of tin perovskite and its interfaces.…”

“…39,40 Despite that great promise, the best performance of carbon-based tin PSC resides at 4.22 %, 19 whereas the efficiency of planar tin PSC is aggressively evolving over 9 %. 14,15,27,28,[32][33][34]41 One reason is that carbon does not reflect visible light, unlike Au or Ag in planar PSC, 39 and suffers from poor hole selectivity because of rapid charge recombination, thereby limiting significantly this otherwise promising technology.…”

Passivation Properties and Formation Mechanism of Amorphous Halide Perovskite Thin Films

“…[ 13 ] Herein it is shown that the addition of more MAAc during synthesis both inhibits the crystallization reaction, and increases the rate of desolvation, leading to formation of amorphous perovskite films and the incorporation of acetate in the films. The promising passivating properties of these films on crystalline perovskite, along with recent results using amorphous tin halide films to improve perovskite solar cells, [ 14 ] bring up the intriguing possibility of using amorphous passivating contacts for record solar cell performance, as has been demonstrated with crystalline silicon. [ 10,15 ]…”